Since a storage communication requires higher communication performance than an inter-server communication, a different network has conventionally been provided for each of the communications. The inter-server communication network is called a local area network (LAN), and the storage communication network is called a storage area network (SAN).
However, with the recent progress of high-speed Ethernet, an integrated network has been realized by integrating the inter-server communication with the storage communication. A Fibre Channel over Ethernet (FCoE) is the technology with the Ethernet for processing a packet of a Fibre Channel (FC).
A conventional FC device may be accessed from a system using the FCoE through an appropriate gateway device. It is a method for configuring a new integrated network system while utilizing existing resources.
FIG. 1A illustrates a configuration of a conventional system.
A system 11 includes an Ethernet switch 12, an FC switch 13, a server 14-i (i=1˜4), and storage 15-i. 
The Ethernet switch 12 performs processes such as routing and transforming a packet, etc.
The Ethernet switch 12 has a gateway using N_port ID virtualization (NPIV), and is connected to the FC switch 13 using the NPIV.
The NPIV refers to the technology of virtualizing the ID of an N_Port and allows a physical port (N_Port) to have a plurality of port names and fabric addresses (N_Port ID).
A plurality of devices (servers 14-1 and 14-2, storage 15-1 and 15-2) are connected to the Ethernet switch 12, and the Ethernet switch 12 presents the FC switch 13 with a plurality of devices as if they were one device using the NPIV.
The Ethernet switch 12 is connected to the FC switch 13, servers 14-1 and 14-2, and the storage 15-1 and 15-2 through a network such as a LAN etc.
The port to which the FC switch 13 of the Ethernet switch 12 has the function of transform the FCoE and the FC. The function assigns a unique MAC address to the FC switch 13, removes the capsule of the FCoE from the FCoE packet transmitted outside from the port, and transmits an FC packet. The function capsules the FC packet received from the port into an FCoE packet.
The FC switch 13 is connected to the Ethernet switch 12, the servers 14-3 and 14-4, and the storage 15-3 and 15-4.
An FC-SAN is configured by the FC switch 13, the servers 14-3 and 14-4, and the storage 15-3 and 15-4.
In the system 11 in FIG. 1A, the FCoE network is connected to the SAN.
There also is a system in which SANs are connected.
FIG. 1B illustrates a configuration of another conventional system.
A system 21 includes an FC switch 22, an FC switch 23, a server 24-i (i=1˜4), and storage 25-i. 
The FC switch 22 performs processes of routing and transforming a packet, etc.
The FC switch 22 has a gateway using an NPIV, and is connected to the FC switch 23 using the NPIV.
A plurality of units (servers 24-1 and 24-2, storage 25-1 and 25-2) are connected to the FC switch 22, and the FC switch 22 presents the FC switch 23 with a plurality of devices as if they were one device using the NPIV.
The FC switch 22 is connected to the FC switch 23, the servers 24-1 and 24-2, and the storage 25-1 and 25-2.
The FC switch 23 is connected to the FC switch 22, the servers 24-3 and 24-4, and the storage 25-3 and 25-4.
An FC-SAN is configured by the FC switch 23, the servers 24-3 and 24-4, and the storage 25-3 and 25-4.
The route of a packet when the packet is transmitted between the FCoE devices in the system in FIG. 1A is described below.
FIG. 2 illustrates a communication between conventional FCoE devices.
FIG. 2 illustrates a communication between the server 14-1 and the storage 15-2.
When a packet is transmitted from the server 14-1 to the storage 15-2, the packet is transmitted from the server 14-1 to the Ethernet switch 12, transferred from the Ethernet switch 12 to the FC switch 13, transmitted from the FC switch 13 to the Ethernet switch 12, and transmitted from the Ethernet switch 12 to the storage 15-2.
Thus, in the communication between the devices under the NPIV connected to the Ethernet switch 12, a packet is transmitted through the FC switch 13.
In the conventional system, although a communication is performed between the devices under the NPIV, the packet is transmitted through an external switch. Therefore, the path is long and the communication latency becomes large. Furthermore, there is a communication bottleneck between switches.
[Patent Document 1] Japanese Laid-open Patent Publication No. 2011-76582
[Patent Document 2] Japanese Laid-open Patent Publication No. 2008-258917